golang[82]-viper-

viper中将map[interface{}]interface{}转换为map[string]interface{} 的逻辑

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func insensitiviseMap(m map[string]interface{}) {
for key, val := range m {
switch val.(type) {
case map[interface{}]interface{}:
// nested map: cast and recursively insensitivise
val = ToStringMap(val)
insensitiviseMap(val.(map[string]interface{}))
case map[string]interface{}:
// nested map: recursively insensitivise
insensitiviseMap(val.(map[string]interface{}))
}

lower := strings.ToLower(key)
if key != lower {
// remove old key (not lower-cased)
delete(m, key)
}
// update map
m[lower] = val
}
}

// ToString casts an interface to a string type.
func ToString(i interface{}) string {
v, _ := ToStringE(i)
return v
}

// ToStringMap casts an interface to a map[string]interface{} type.
func ToStringMap(i interface{}) map[string]interface{} {
v, _ := ToStringMapE(i)
return v
}

// ToStringMapE casts an interface to a map[string]interface{} type.
func ToStringMapE(i interface{}) (map[string]interface{}, error) {
var m = map[string]interface{}{}

switch v := i.(type) {
case map[interface{}]interface{}:
for k, val := range v {
m[ToString(k)] = val
}
return m, nil
case map[string]interface{}:
return v, nil
case string:
err := jsonStringToObject(v, &m)
return m, err
default:
return m, fmt.Errorf("unable to cast %#v of type %T to map[string]interface{}", i, i)
}
}

// ToStringE casts an interface to a string type.
func ToStringE(i interface{}) (string, error) {
i = indirectToStringerOrError(i)

switch s := i.(type) {
case string:
return s, nil
case bool:
return strconv.FormatBool(s), nil
case float64:
return strconv.FormatFloat(s, 'f', -1, 64), nil
case float32:
return strconv.FormatFloat(float64(s), 'f', -1, 32), nil
case int:
return strconv.Itoa(s), nil
case int64:
return strconv.FormatInt(s, 10), nil
case int32:
return strconv.Itoa(int(s)), nil
case int16:
return strconv.FormatInt(int64(s), 10), nil
case int8:
return strconv.FormatInt(int64(s), 10), nil
case uint:
return strconv.FormatInt(int64(s), 10), nil
case uint64:
return strconv.FormatInt(int64(s), 10), nil
case uint32:
return strconv.FormatInt(int64(s), 10), nil
case uint16:
return strconv.FormatInt(int64(s), 10), nil
case uint8:
return strconv.FormatInt(int64(s), 10), nil
case []byte:
return string(s), nil
case template.HTML:
return string(s), nil
case template.URL:
return string(s), nil
case template.JS:
return string(s), nil
case template.CSS:
return string(s), nil
case template.HTMLAttr:
return string(s), nil
case nil:
return "", nil
case fmt.Stringer:
return s.String(), nil
case error:
return s.Error(), nil
default:
return "", fmt.Errorf("unable to cast %#v of type %T to string", i, i)
}
}

// jsonStringToObject attempts to unmarshall a string as JSON into
// the object passed as pointer.
func jsonStringToObject(s string, v interface{}) error {
data := []byte(s)
return json.Unmarshal(data, v)
}


// From html/template/content.go
// Copyright 2011 The Go Authors. All rights reserved.
// indirectToStringerOrError returns the value, after dereferencing as many times
// as necessary to reach the base type (or nil) or an implementation of fmt.Stringer
// or error,
func indirectToStringerOrError(a interface{}) interface{} {
if a == nil {
return nil
}

var errorType = reflect.TypeOf((*error)(nil)).Elem()
var fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()

v := reflect.ValueOf(a)
for !v.Type().Implements(fmtStringerType) && !v.Type().Implements(errorType) && v.Kind() == reflect.Ptr && !v.IsNil() {
v = v.Elem()
}
return v.Interface()
}